The present invention generally relates to carpet tufting machines and in particular to a yarn feed system or pattern attachment for controlling the feeding of individual yarns to the needles of a tufting machine.
In the carpet-tufting field, there is considerable emphasis placed on developing new, eye-catching carpet patterns to keep up with changing consumer tastes and increased competition in the marketplace. With the introduction of computer controls for tufting machines, as disclosed in U.S. Pat. No. 4,867,080, greater precision and variety in designing and producing tufted patterned carpets has been possible while also enabling enhanced production speeds. In addition, computerized design centers have been developed, such as shown in U.S. Pat. No. 5,058,518, to enable designers to design and develop visual representations of patterns on a computer and generate the pattern requirements such a yarn feed, pile heights, etc. that will be input into a tufting machine controller for forming such patterns.
Traditionally, pattern attachments such as roll or scroll pattern attachments have been used for controlling the feeding of selected groups of yarns to the needles of a tufting machine having such a pattern attachment. Such roll and/or scroll pattern attachments include a series of yarn feed rolls that feed the selected groups of yarns to selected ones of the needles. By controlling the operation of these feed rolls, the rate of feed of the yarns to the needles is controlled for varying the pile heights of the tufts of yarn formed in a backing material passing through the tufting machine, so as to enable some tufts of yarn to be back-robbed and hidden by adjacent tufts in order to form different pattern repeats across the width of the backing material.
A significant problem, however, that exists with the use of such traditional pattern attachments and even with more recently developed scroll type pattern attachments such as disclosed in U.S. Pat. No. 6,244,203, which discloses a servo-motor controlled scroll type pattern attachment for a tufting machine, has been the requirement for tube banks that extend from the pattern attachment feed rolls at varying lengths across the tufting machine for feeding the yarns from the pattern attachment feed rolls to the needles. Such tube banks include a plurality of tubes of varying lengths, along which the yarns are urged or fed to their respective needles. The problem with such tube banks generally has been that the yarns passing through the longer tubes are typically subjected to increased drag or friction as they are passed along the increased length of their tubes, such that it has been difficult to achieve high amounts of precision and responsiveness to changes in the pattern across the width of the carpet. The use of the tube banks further adds a significant cost both in terms of manufacture and set up of the machines, as well as significantly increasing the complexity of operation of the tufting machines.
In addition, systems such as disclosed in U.S. Pat. Nos. 6,244,203 and 6,213,036 have attempted to achieve greater precision and control of the feeding of the yarns by the pattern attachment through the use of an increased number of feed rolls and drive motors for feeding selected ones of the yarns to selected needles. However, as the number of yarn feed rolls and number of motors associated therewith for driving such individual yarn feed rolls is increased, there is likewise a corresponding increase in the costs of such pattern attachments. In addition, increasing the number of motors and feed rolls further increases the complexity of manufacturing such pattern attachments, as well as the set up of such attachments as a part of a tufting machine when the machine is installed in the field. In addition, the reliability of such systems generally becomes of greater concern, given the increased number of feed devices being controlled by the tufting machine controller and the corresponding amount of wiring and electrical connections that must be assembled and made in the field with the set up of the tufting machine and pattern attachments.
Accordingly, it can be seen that a need exists for a system that addresses these and other related and unrelated problems in the art.
Briefly described, the present invention generally relates to a yarn feed system or pattern yarn feed attachment that is removably mounted on a tufting machine and is adapted to feed a series of yarns individually to each of the needles of the tufting machine. The feeding of the individual yarns to each needle is independently controlled by the yarn feed system to provide enhanced precision and control as needed or desired to form tufts of yarn in a backing material being passed through the tufting machine according to programmed carpet pattern instructions. The yarn feed system of the present invention generally comprises a yarn feed unit that can be constructed as a standardized, self-contained unit or attachment that can be releasably mounted to and/or removed from the tufting machine as a unit, and enables multiple yarn feed units to be mounted to the tufting machine in series as needed depending on the number of needles in the tufting machine.
The yarn feed unit of the present invention generally includes a frame defining a housing in which a series of yarn feed devices are received and supported. Each of the yarn feed devices generally includes a drive motor that can be releasably mounted within the frame and drives a drive roll, and an idler roll that is biased toward engagement with the drive roll to engage a yarn therebetween. A series of yarn feed tubes feed individual yarns from a yarn supply to each of the yarn feed devices, with the yarns being engaged and guided between the drive and idler rolls of their associated yarn feed devices. The drive motors of the yarn feed devices are independently controlled so as to feed the yarns at desired rates to selected ones of the needles of the tufting machine.
A series of yarn feed controllers or multiple drive units are received and mounted within a cage or support mounted within the housing of the yarn feed unit. Each of the yarn feed controllers generally includes a controller board or module, and typically will have a primary control processor mounted on the board and a series of motor controllers or drives each connected to the primary control processor. A secondary control processor further can be provided to provide for backup and redundancy for each yarn feed controller to increase or enhance reliability thereof. Each of the motor controllers generally controls at least one of the drive motors of the yarn feed devices in accordance with control instructions provided by the primary and/or secondary control processors. The motor controllers also provide feedback to the control processor(s) regarding the operation of the drive motors being controlled by each motor controller.
The control processors of each of the yarn feed controllers further are electrically connected to a system control unit or controller, which monitors the feedback from the motor controllers, and provides pattern control instructions to the control processor(s) of each of the yarn feed controllers. These instructions are in turn communicated to the motor controllers for controlling the speed of each of the drive motors to individually control the feeding of each yarn to its corresponding needle to form the desired or programmed pattern. The system controller can be provided as a separate workstation having an input mechanism, such as a keyboard, mouse, etc. and a monitor and generally will be in communication with a tufting machine controller that monitors various operative elements of the tufting machine. Alternatively, the system controller and/or its functions can be included as part of the tufting machine controller.
In addition, the system controller can be connected to a design center on which an operator can design a desired carpet patterns and which generally includes a computer that will calculate the parameters of such a design, including parameters including yarn feed rates, pile heights, stitch length, etc. This information can be created as a pattern data file, designed or programmed using pattern design software or a design system and input or electronically communicated to the tufting machine controller and/or the system controller of the yarn feed unit via a network connection, disk or other file transfer. Alternatively, the tufting machine controller or the system controller can be provided with the design center components or functionality programmed therein so as to enable the operator to design or program carpet patterns at the tufting machine.
The yarn feed unit of the present invention thus provides individualized control of the feeding of each of a series of yarns to each of the needles of the tufting machine according to programmed pattern instructions to form a desired pattern. The yarn feed unit of the present invention further enables the manufacture of standardized yarn feed attachments or units that can be manufactured, tested, stored in inventory, and thereafter removably installed on a tufting machine without requiring the custom design and installation of such a pattern attachment, and without requiring a costly and time-consuming set-up of the machine and tube bank array therefor. In addition, the housing of the yarn feed unit can be formed with a substantially open design, and the yarn feed unit can include a series of fans and heat sinks being provided for the yarn feed controllers to promote the efficient dissipation of heat from the yarn feed unit for the efficient and reliable operation of the electronic components thereof.
Various features, objects and advantages of the present invention will become apparent to those skilled in the art upon reading the following detailed description when taken in conjunction with the accompanying drawings.